Production of hydrocarbon liquids

Abstract

A process to efficiently convert organic feedstock material into liquid non-oxygenated hydrocarbons in the C 5 to C 12 carbon skeleton range is disclosed. The process can utilize gaseous, liquid or solid organic feedstocks containing carbon, hydrogen and, optionally, oxygen. The feedstock may require preparation of the organic feedstock for the process and is converted first into a synthesis gas containing carbon monoxide and hydrogen. The synthesis gas is then cleaned and conditioned and extraneous components removed, leaving substantially only the carbon monoxide and hydrogen. It is then converted via a series of chemical reactions into the desired liquid hydrocarbons. The hydrocarbons are suitable for combustion in a vehicle engine and may be regarded a replacement for petrol made from fossil fuels in the C 5 to C 12 carbon backbone range. The process also recycles gaseous by-products back through the various reactors of the process to maximize the liquid hydrocarbon in the C 5 to C 12 carbon skeleton range yield.

What is claimed is: 
     
       1. A process for producing a C 5  to C 12  hydrocarbon fuel from organic material, comprising:
 a) applying a heat source to heat an organic feedstock and oxygen at substoichiometric conditions to a temperature sufficient for partial combustion of said organic feedstock to occur and then ceasing application of said heat source once partial combustion has commenced; 
 b) partially combusting said organic feedstock so as to produce a synthesis gas stream, said synthesis gas stream containing at least carbon monoxide, carbon dioxide and hydrogen; 
 c) substantially removing unwanted solid and liquid matter comprising oxides, ash and hydrocarbons having a carbon skeleton of greater than C 10  from said synthesis gas stream to produce a first cleaned synthesis gas stream containing at least carbon monoxide, carbon dioxide and hydrogen; 
 d) compressing said first cleaned synthesis gas stream and substantially removing water; 
 e) conditioning and further cleaning the first cleaned synthesis gas stream by substantially removing inorganic elements and inorganic compounds from said first cleaned synthesis gas stream to provide a second cleaned synthesis gas stream containing at least carbon monoxide, carbon dioxide and hydrogen; 
 f) selectively removing carbon dioxide from said second cleaned synthesis gas stream; 
 g) catalytically treating said second cleaned synthesis gas stream to produce a first mixture containing at least carbon monoxide, hydrogen and dimethyl ether; 
 h) collecting said dimethyl ether from said first mixture; 
 i) catalytically reacting said dimethyl ether to produce a second mixture containing at least alkanes; and 
 j) selectively obtaining said alkanes having from a C 5  to C 12  skeleton from said second mixture. 
 
     
     
       2. The process for producing a C 5  to C 12  hydrocarbon fuel from organic material as defined in  claim 1 , wherein the hydrocarbons having a carbon skeleton of greater than C 10  are light oils, tar or olefins. 
     
     
       3. The process for producing a C 5  to C 12  hydrocarbon fuel from organic material as defined in  claim 1 , wherein step (e) further comprises removing at least a portion of the alkanes, alkenes and alkynes contained in said first cleaned synthesis gas stream and reacting said removed alkanes, alkenes and alkynes in a reformer to produce at least carbon monoxide, carbon dioxide and hydrogen. 
     
     
       4. The process for producing a C 5  to C 12  hydrocarbon fuel from organic material as defined in  claim 3 , wherein the reformer is an autothermal reformer and wherein the alkanes, alkenes and alkynes are reacted in the reformer at a temperature of from about 950° C. to about 1100° C. and at a pressure of less than about 9790 kpa. 
     
     
       5. The process for producing a C 5  to C 12  hydrocarbon fuel from organic material as defined in  claim 1 , wherein the carbon dioxide is selectively removed from the second cleaned synthesis gas stream by an acid/gas carbon dioxide removal process. 
     
     
       6. The process for producing a C 5  to C 12  hydrocarbon fuel from organic material as defined in  claim 1 , wherein the second cleaned synthesis gas stream is catalytically treated to produce the first mixture comprising at least carbon monoxide, hydrogen and dimethyl ether using a base metal catalyst. 
     
     
       7. The process for producing a C 5  to C 12  hydrocarbon fuel from organic material as defined in  claim 6 , wherein the second cleaned synthesis gas stream is catalytically treated to produce the first mixture comprising at least carbon monoxide, hydrogen and dimethyl ether using the base metal catalyst at a temperature of from about 225° C. to about 300° C. and at a pressure of 2.5 Mpa to 7.5 Mpa; the base metal catalyst being a nickel catalyst, a copper catalyst, a zinc catalyst, or an iron catalyst. 
     
     
       8. The process for producing a C 5  to C 12  hydrocarbon fuel from organic material as defined in  claim 1 , wherein the dimethyl ether in the first mixture is catalytically treated to produce a second mixture containing at least alkanes using a zeolite catalyst. 
     
     
       9. The process for producing a C 5  to C 12  hydrocarbon fuel from organic material as defined in  claim 8 , wherein the zeolite catalyst has a ratio of silica to alumina of from about 298:1 to about 2000:1. 
     
     
       10. The process for producing a C 5  to C 12  hydrocarbon fuel from organic material as defined in  claim 9 , wherein the dimethyl ether in the first mixture is catalytically treated at a temperature of from about 350° C. to about 450° C. and at a pressure of from about 140 kpa to about 350 kpa. 
     
     
       11. The process for producing a C 5  to C 12  hydrocarbon fuel from organic material as defined in  claim 1 , wherein the C 5  to C 12  alkanes are selectively obtained from the second mixture by distillation. 
     
     
       12. The process for producing a C 5  to C 12  hydrocarbon fuel from organic material as defined in  claim 1 , wherein the second mixture further contains alkenes, alkynes, aromatic compounds, or naphthalenes. 
     
     
       13. The process for producing a C 5  to C 12  hydrocarbon fuel from organic material as defined in  claim 12 , wherein the alkenes, alkynes, aromatic compounds, or naphthalenes are selectively obtained from the second mixture by distillation. 
     
     
       14. The process for producing a C 5  to C 12  hydrocarbon fuel from organic material as defined in  claim 1 , wherein step (f) further comprises using a water/gas shift reaction. 
     
     
       15. The process for producing a C 5  to C 12  hydrocarbon fuel from organic material as defined in  claim 14 , wherein the water/gas shift reaction increases the ratio of hydrogen to carbon monoxide. 
     
     
       16. The process for producing a C 5  to C 12  hydrocarbon fuel from organic material as defined in  claim 15 , wherein the ratio of hydrogen to carbon monoxide is from about 1:1 to about 1:2. 
     
     
       17. The process for producing a C 5  to C 12  hydrocarbon fuel from organic material as defined in  claim 1 , wherein the organic feedstock is a solid, a gas or a liquid. 
     
     
       18. A process for producing a C 5  to C 12  hydrocarbon fuel from organic material comprising:
 a) applying a heat source to heat an organic feedstock and oxygen at substoichiometric conditions up to a temperature of about 800° C. and then ceasing application of said heat source once partial combustion in an exothermic reaction has commenced; 
 b) partially combusting said organic feedstock without continuous application of an external heat source so as to produce a synthesis gas stream, said synthesis gas stream containing at least carbon monoxide, carbon dioxide and hydrogen; 
 c) substantially removing unwanted solid and liquid matter comprising oxides, ash and hydrocarbons having a carbon skeleton of greater than C 10  from said synthesis gas stream to produce a first cleaned synthesis gas stream containing at least carbon monoxide, carbon dioxide and hydrogen; 
 d) compressing said first cleaned synthesis gas stream and substantially removing water; 
 e) removing at least a portion of the alkanes, alkenes and alkynes from said first cleaned synthesis gas stream; 
 f) reacting said removed alkanes, alkenes and alkynes of step e) with a catalyst to produce a supplemental gas stream containing at least carbon monoxide, carbon dioxide and hydrogen; 
 g) removing inorganic elements and inorganic compounds from said first cleaned synthesis gas stream to provide a second cleaned synthesis gas stream containing at least carbon monoxide, carbon dioxide and hydrogen; 
 h) merging said second cleaned synthesis gas stream with said supplemental gas stream; 
 i) selectively removing carbon dioxide from said second cleaned synthesis gas stream merged with said supplemental gas stream; 
 j) catalytically treating said second cleaned synthesis gas stream merged with said supplemental gas stream to produce a first mixture containing at least carbon monoxide, hydrogen and dimethyl ether; 
 k) collecting said dimethyl ether from said first mixture; 
 l) catalytically reacting said dimethyl ether to produce a second mixture containing at least alkanes; and 
 m) selectively obtaining said alkanes having from a C 5  to C 12  skeleton from said second mixture. 
 
     
     
       19. A process for producing a C 5  to C 12  hydrocarbon fuel from organic material comprising:
 a) forming a first synthesis gas stream by the steps of
 (i) applying a heat source to heat an organic feedstock and oxygen at substoichiometric conditions up to a temperature of about 800° C. and then ceasing application of said heat source once partial combustion in an exothermic reaction has commenced, 
 (ii) partially combusting said organic feedstock without continuous application of a heat source so as to produce a synthesis gas stream, said synthesis gas stream containing at least carbon monoxide, carbon dioxide and hydrogen, 
 (iii) substantially removing unwanted solid and liquid matter comprising oxides, ash and hydrocarbons having a carbon skeleton of greater than C 10  from said synthesis gas stream to produce a first cleaned synthesis gas stream containing at least carbon monoxide, carbon dioxide and hydrogen; 
 (iv) recycling and enjoining said hydrocarbons having a carbon skeleton greater than C 10  to step a)(ii) for partial combustion, 
 (v) compressing said first cleaned synthesis gas stream and substantially removing water, and 
 (vi) removing at least a portion of the alkanes, alkenes and alkynes from said first cleaned synthesis gas stream; 
 
 b) forming a second cleaned synthesis gas stream by the steps of
 (i) reacting said removed alkanes, alkenes and alkynes of step a)(vi) with a catalyst to produce at least carbon monoxide, carbon dioxide and hydrogen, and 
 (ii) selectively removing carbon dioxide from said second cleaned synthesis gas stream; 
 
 c) merging said first cleaned synthesis gas stream and said second cleaned synthesis gas stream so as to provide a merged cleaned synthesis gas stream; 
 d) catalytically treating said merged synthesis gas stream to produce a first mixture containing at least carbon monoxide, hydrogen and dimethyl ether; 
 e) collecting said dimethyl ether from said first mixture and recycling said carbon monoxide back into said second cleaned synthesis gas stream for additional catalytic treatment; 
 f) catalytically reacting said dimethyl ether to produce a second mixture containing at least alkanes; and 
 g) selectively obtaining said alkanes having from a C 5  to C 12  skeleton from said second mixture.